This invention relates to thermal inkjet imaging. More particularly, this invention relates to a method and apparatus to compensate for drop quantity variation.
High fidelity reproduction of images on media in inkjet imaging operations is more effectively accomplished if the quantity of colorants deposited onto the media can be carefully controlled. The quantity of ink ejected from the nozzles can vary between ejections. These variations increase the difficulty of accurately reproducing the color of the image on the media. A need exists for a method and apparatus to more effectively control the quantity of ink deposited onto media during an imaging operation.
Accordingly, a method includes receiving a value related to a temperature of a printhead and determining a function value related to an ink drop quantity ejected by the printhead using the value. The method further includes transforming an intensity value using the function value to form a transformed intensity value.
A temperature compensation system includes a temperature sensor configured to provide a signal related to a temperature of a printhead. In addition, the temperature compensation system includes a controller arranged to receive the signal and configured to determine a value related to an ink drop quantity ejected by the printhead and configured to determine a transformed intensity value using the value and an intensity value.
An inkjet imaging device to form an image on media corresponding to image data includes a printhead arranged to receive drive signals and configured to eject ink onto the media according to the drive signals. In addition, the inkjet imaging device includes a temperature sensor configured to provide a signal related to a temperature of the printhead. Furthermore, the inkjet imaging device includes a controller arranged to receive the signal and the image data. With the controller configured to determine a value related to ink drop quantity ejected by the printhead, configured to determine an intensity value from the image data, configured to determine a transformed intensity value using the value and the intensity value, and configured to generate data using the transformed intensity value. The inkjet imaging device also includes a driver circuit arranged to receive the data and configured to generate the drive signals according to the data.